1. Field of the Invention
The present invention relates to a radiation detector for detecting radiation incident on a detection zone of the detector, of the type having detector elements which are arranged in the form of an array, each having scintillator and a photodiode interacting with the latter.
2. Description of the Prior Art
In radiation detectors of this type which are used for example in the form of so-called multi-row detectors in computed tomography systems, in order to keep signal paths as short as possible, active semiconductor components are mounted as near as possible to the detector area on which the X-ray radiation strikes.
These active semiconductor components are sensitive to X-ray radiation and may be damaged or even destroyed by X-ray radiation.
FIG. 1 shows a known X-ray radiation detector having a number of detector elements, each formed by a scintillator 3 and a photodiode 6, arranged in a substrate. An X-ray beam, originating from a focus F, is incident on the detectors. Despite being gated by diaphragm plates 1 so that margin rays BR reach the extreme edges of the detectors, scattered radiation can nevertheless reach semiconductor components 2, which are disposed at sides of the detector array on a substrate 7, and are connected to photodiodes 6 by bonding wires 5. This scattered radiation arises because X-rays, designated R, can penetrate through the scintillator elements 3 at the edges, causing scattering which results in scattered radiation reaching the semiconductor components 2.
In order to shield the semiconductor components 2 in particular also against scattered radiation SR arising in the scintillators 3, it is possible, in the manner shown in FIG. 2, to position material 4 that greatly absorbs X-ray radiation, e.g. lead, between a scintillator 3 situated at the edge of the array and the semiconductor component 2.
This procedure is costly and complicated since a separate individual part has to be designed, produced and incorporated. Moreover, during incorporation, the bonding wires 5 between the photodiodes 6 of the detector elements and the semiconductor component 2 may be damaged.
Alternatively, it is possible to mount the semiconductor components 2 farther away from the active detector area, which entails, besides the higher susceptibility to interference, a great outlay, since the lines emerging from the numerous photodiodes have to be led via cables and, if appropriate, plugged connections to the semiconductor components 2.